Discussion Starter · #1 ·
So i recently rebuilt my 400ex with a 440 big bore kit. I installed a new cylinder piston rings racing manual tensioner and all new gaskets and o rings. I set the valve clearance to the service manual specs and was getting 150 psi on the compression test. Wouldnt start. So i tinkered woth the valves until i got it 120 psi. (Partzilla says should be between 100-128). And it still wont start. Ive got a brand new spark plug. Its getting fuel and everything. My question is what should i do about this. Should i set them back to .004 int and .005 ex and leave it at 150 psi? Ive also been hearing that i should jet the carb. What sizes should i use? Ive got so much time and money into this project and just am completely stuck right now. Someone please help...